1. Field of the Invention
This invention relates to an improvement on an apparatus such as a camera adapted to use a film cartridge which is provided with a movable light shield cover.
2. Description of the Related Art
The conventional cartridge loading device of a camera of the kind adapted to use a film cartridge having a movable light shield cover for opening and closing a film inlet/outlet opening has included a support member which is arranged on a cartridge chamber lid to support the film cartridge, as disclosed in Japanese Patent Application No. HEI 5-342050. The support member is urged by a spring to push the film cartridge into a cartridge chamber (for loading) when the cartridge chamber lid is closed.
The conventional device which is arranged as shown by way of example in FIG. 14, however, necessitates exertion of a large force in inserting the film cartridge 201, because an engaging part 201a of the film cartridge 201 must be caused to engage a light shield cover driving member (not shown) for opening and closing the movable light shield cover (not shown) of the film cartridge 201. Therefore, in order to have the film cartridge set in a correct position, a strong spring is used for urging the support member. As a result, the strong spring force is applied also to a fork 202, as shown in FIG. 14. The strong spring force then eventually comes to generate a frictional force on a base plate 204 by which a fork gear 203 is supported.
Assuming that the spring force is expressed as P, the radius of contact as R and the coefficient of friction as .mu., the frictional torque Tf of the above-stated friction can be expressed as follows: EQU Tf=.mu..multidot.P.multidot.R
Since the spring force P must be 700 gf or thereabout, the frictional torque Tf becomes about 50 gcm, which becomes a load in transporting a film. The load not only retards the film transport speed but also causes an increase in the electric energy consumption.